2010 MotoGP track action got underway at Sepang on Wednesday morning, when factory test riders began lapping the Malaysian Grand Prix circuit.

Unlike in previous years, the first day of each pre-season test is now restricted to test riders only, with MotoGP race riders then taking to the track on days two and three.

The test riders listed as riding at Sepang are: Norihiko Fujiwara and Wataru Yoshikawa (both Yamaha), Kosuke Akiyoshi (Honda), Nobuatsu Aoki (Suzuki) and Vittoriano Guareschi (Ducati).

The main task of the test riders will be to shakedown the new 2010 machines to ensure maximum track time for the race riders on Thursday and Friday.

Thursday at Sepang will also see the official Fiat Yamaha team launch, when Valentino Rossi and Jorge Lorenzo - first and second in the 2009 world championship - will unveil their 2010 race colours and talk about the forthcoming season.

After this week's test, teams and riders will return to Sepang from February 24-26 before the third and final pre-season test is held at Qatar from March 17-19.

The opening round of the 2010 season will also take place at Qatar, from April 9-11.